Project Summary/Abstract Nicotinic acetylcholine receptors (nAChRs) are broadly expressed in the CNS where they modulate the release of key neurotransmitters involved in learning, mood, and reward. nAChRs are also found in diverse non- neuronal tissues including immune cells, skin, gastro-intestinal epithelium and breast tumors. Research in our laboratory, which has been funded by R01 GM103801 and a project of P01 GM48677, is focused on enabling mechanistic understanding of how nAChRs regulate signaling at the single cell and systems levels. Venoms from predatory marine snails, known as Conus, are the richest known source of diverse, evolutionarily-refined ligands that target nAChRs. We have made substantial progress in developing peptides from these venoms that are selective for ?6 subunit-containing subtypes of nAChRs. These peptides have been widely used to demonstrate that specific nAChR subtypes modulate key dopaminergic circuits that are strongly implicated in the addictive properties of drugs and in movement disorders such as Parkinson?s disease. Separately, we made groundbreaking progress in validating the ?9?10 nAChR as a novel target for treatment of neuropathic pain. We enabled such progress by developing potent and highly selective conopeptides. Over the next 5 years, an overarching goal of our research program will be to develop robust suites of potent, highly selective conopeptide-based probes for the study of additional subtypes of nAChRs. We will continue to exploit the resulting compounds for applications in medicine. A particular focus will be to develop new ligands with high specificity for nAChR subtypes of non-neuronal cells. The most widely expressed nAChRs in non-neuronal cells have ?7, ?9, ?10 and ?5 subunits where our insight into function is limited. We will utilize the resulting peptide probes to examine the structures and functions of these nAChR subtypes. We have demonstrated that block of ?9?10 nAChRs is analgesic in multiple animal models of neuropathic pain. Of high interest to us, is that selective conopeptides not only alleviate neuropathic pain, but they also prevent development of, or accelerate recovery from, nerve injury. Thus, the underlying therapeutic mechanism has significant implications for truly disease-modifying therapies. We will test the hypothesis that modulation of nAChRs in non-neuronal cells is key to understanding disease modification observed in models of trauma-, chemotherapy- and diabetes-induced nerve injury.